Higher-Intensity Walking May Lower the Risk of TKA in Patients with Knee OA
Patients with knee osteoarthritis (OA) who walk at a moderate-to-vigorous intensity may delay their need for total knee arthroplasty (TKA), according to new research findings presented at the 2018 ACR/ARHP Annual Meeting.
This study was conducted to help answer the question: Will walking more increase a patient’s risk of worsening damage to structures in the knee joint, leading to TKA? There is contradictory evidence in this area, and one reason may be that patients walk at different intensities. Researchers at the University of Delaware conducted a study to learn more about the association of walking intensity with TKA risk over a 5-year period in adults with or at high risk of knee OA.
Using data from the Osteoarthritis Initiative (OAI), the researchers included participants who did not have TKA at or before a 48-month follow-up visit. They quantified different walking intensities by step cadence recorded on an accelerometer:
- Non-walking: Less than 1 step/minute
- Very light walking: 1 to 49 steps/minute
- Light walking: 50 to 100 steps/minute
- Moderate to vigorous walking: More than 100 steps/minute
They quantified time to TKA in months from the baseline visit date to the surgery date if it occurred in the subsequent 5 years, or at the 108-month visit. Any participants who did not have TKA at the 108-month visit or who were lost to follow-up were censored.
The researchers examined the effects of replacing time spent not walking with walking at either very light, light, or moderate-to-vigorous intensities with TKA risk over 5 years using isotemporal substitution within a Cox proportional hazard model, calculating hazard ratios (HR) and 95% confidence interval (CI) adjusted for potential confounders. They repeated these analyses on participants with radiographic and symptomatic knee OA.
At baseline, there were 1,854 participants without TKA who wore their accelerometer for at least 4 out of 7 days. They had a mean age of 65 years and a mean body-mass index (BMI) of 28.4 and 55% were female. Over 5 years, 108 participants underwent TKA. Participants who replaced 5 minutes per day of non-walking time with 5 minutes per day of walking at moderate-to-vigorous intensity reduced their risk of TKA by 16% (HR 0.84, 95%CI [0.72, 0.98]). Very light and light intensity walking had no effect. Similar results were found when the researchers analyzed samples of patients with radiographic and symptomatic knee OA.
“Our findings suggest that small changes in walking behavior may delay the need for TKA in people with or at high risk of knee OA,” said Hiral Master, PT, MPH, a PhD candidate in biomechanics and movement science at the University of Delaware and the study’s lead author.
“Clinicians should consider encouraging their patients with or at high risk of knee OA to go for a brisk walk for 5 to 10 continuous minutes each and every day.”
Master H, Thoma L, Christensen M, et al. Friend or foe: does walking at higher intensities increase or decrease the risk of total knee arthroplasty over five years? (Abstract 1166). Presented at the ACR/ARHP Annual Meeting, October 21-24, 2018, in Chicago, Illinois.